From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42653) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZzpEO-0008HW-0J for qemu-devel@nongnu.org; Fri, 20 Nov 2015 12:12:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZzpEN-0004i3-19 for qemu-devel@nongnu.org; Fri, 20 Nov 2015 12:12:15 -0500 References: <1448029742-19771-1-git-send-email-pl@kamp.de> From: John Snow Message-ID: <564F5465.5070800@redhat.com> Date: Fri, 20 Nov 2015 12:12:05 -0500 MIME-Version: 1.0 In-Reply-To: <1448029742-19771-1-git-send-email-pl@kamp.de> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] tests: fix cdrom_pio_impl in ide-test List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Lieven , qemu-devel@nongnu.org, qemu-block@nongnu.org Cc: kwolf@redhat.com, peter.maydell@linaro.org On 11/20/2015 09:29 AM, Peter Lieven wrote: > The check for the cleared BSY flag has to be performed > before each data transfer and not just before the > first one. > > Commit 5f81724d revealed this glitch as the BSY flag > was not set in ATAPI PIO transfers before. > > While at it fix the desciptions and add a comment before Descriptions, if this can be fixed on apply. > the nested for loop that transfers the data. > > Signed-off-by: Peter Lieven > --- > tests/ide-test.c | 16 ++++++++-------- > 1 file changed, 8 insertions(+), 8 deletions(-) > > diff --git a/tests/ide-test.c b/tests/ide-test.c > index d1014bb..fc1ce52 100644 > --- a/tests/ide-test.c > +++ b/tests/ide-test.c > @@ -699,24 +699,19 @@ static void cdrom_pio_impl(int nblocks) > outb(IDE_BASE + reg_lba_middle, BYTE_COUNT_LIMIT & 0xFF); > outb(IDE_BASE + reg_lba_high, (BYTE_COUNT_LIMIT >> 8 & 0xFF)); > outb(IDE_BASE + reg_command, CMD_PACKET); > - /* HPD0: Check_Status_A State */ > + /* HP0: Check_Status_A State */ > nsleep(400); > data = ide_wait_clear(BSY); > - /* HPD1: Send_Packet State */ > + /* HP1: Send_Packet State */ > assert_bit_set(data, DRQ | DRDY); > assert_bit_clear(data, ERR | DF | BSY); > > /* SCSI CDB (READ10) -- read n*2048 bytes from block 0 */ > send_scsi_cdb_read10(0, nblocks); > > - /* HPD3: INTRQ_Wait */ > + /* HP3: INTRQ_Wait */ > ide_wait_intr(IDE_PRIMARY_IRQ); > > - /* HPD2: Check_Status_B */ > - data = ide_wait_clear(BSY); > - assert_bit_set(data, DRQ | DRDY); > - assert_bit_clear(data, ERR | DF | BSY); > - > /* Read data back: occurs in bursts of 'BYTE_COUNT_LIMIT' bytes. > * If BYTE_COUNT_LIMIT is odd, we transfer BYTE_COUNT_LIMIT - 1 bytes. > * We allow an odd limit only when the remaining transfer size is > @@ -728,6 +723,11 @@ static void cdrom_pio_impl(int nblocks) > for (i = 0; i < DIV_ROUND_UP(rxsize, limit); i++) { > size_t offset = i * (limit / 2); > size_t rem = (rxsize / 2) - offset; > + /* HP2: Check_Status_B */ > + data = ide_wait_clear(BSY); > + assert_bit_set(data, DRQ | DRDY); > + assert_bit_clear(data, ERR | DF | BSY); > + /* HP4: Transfer_Data */ > for (j = 0; j < MIN((limit / 2), rem); j++) { > rx[offset + j] = le16_to_cpu(inw(IDE_BASE + reg_data)); > } > This looks correct. This will definitely fix the race in the test, since it was due to a race where we were reading the data when DRQ was not set. Where I still remain a little confused is the precise flow control that leads to sending an interrupt where BSY is set and DRQ is clear. I'd like to investigate that a little more, but for purposes of rc1 and testing I think this is the right thing to do. For rc1, however: Reviewed-by: John Snow